/*  
*********************************************************************************************************  
*                                                uC/OS-II  
*                                          The Real-Time Kernel  
*                                  MUTUAL EXCLUSION SEMAPHORE MANAGEMENT  
*  
*                          (c) Copyright 1992-2005, Jean J. Labrosse, Weston, FL  
*                                           All Rights Reserved  
*  
* File    : OS_MUTEX.C  
* By      : Jean J. Labrosse  
* Version : V2.80  
*********************************************************************************************************  
*/   
   
#ifndef  OS_MASTER_FILE   
#include "ucos_ii.h"   
#endif   
   
/*  
*********************************************************************************************************  
*                                            LOCAL CONSTANTS  
*********************************************************************************************************  
*/   
   
#define  OS_MUTEX_KEEP_LOWER_8   0x00FFu   
#define  OS_MUTEX_KEEP_UPPER_8   0xFF00u   
   
#define  OS_MUTEX_AVAILABLE      0x00FFu   
   
   
#if OS_MUTEX_EN > 0   
/*  
*********************************************************************************************************  
*                                   ACCEPT MUTUAL EXCLUSION SEMAPHORE  
*  
* Description: This  function checks the mutual exclusion semaphore to see if a resource is available.  
*              Unlike OSMutexPend(), OSMutexAccept() does not suspend the calling task if the resource is  
*              not available or the event did not occur.  
*  
* Arguments  : pevent     is a pointer to the event control block  
*  
*              err        is a pointer to an error code which will be returned to your application:  
*                            OS_NO_ERR          if the call was successful.  
*                            OS_ERR_EVENT_TYPE  if 'pevent' is not a pointer to a mutex  
*                            OS_ERR_PEVENT_NULL 'pevent' is a NULL pointer  
*                            OS_ERR_PEND_ISR     if you called this function from an ISR  
*  
* Returns    : == 1       if the resource is available, the mutual exclusion semaphore is acquired  
*              == 0       a) if the resource is not available  
*                         b) you didn't pass a pointer to a mutual exclusion semaphore  
*                         c) you called this function from an ISR  
*  
* Warning(s) : This function CANNOT be called from an ISR because mutual exclusion semaphores are  
*              intended to be used by tasks only.  
*********************************************************************************************************  
*/   
   
#if OS_MUTEX_ACCEPT_EN > 0   
INT8U  OSMutexAccept (OS_EVENT *pevent, INT8U *err)   
{   
#if OS_CRITICAL_METHOD == 3                            /* Allocate storage for CPU status register     */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
#if OS_ARG_CHK_EN > 0   
    if (err == (INT8U *)0) {                           /* Validate 'err'                               */   
        return (0);   
    }   
    if (pevent == (OS_EVENT *)0) {                     /* Validate 'pevent'                            */   
        *err = OS_ERR_PEVENT_NULL;   
        return (0);   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) {  /* Validate event block type                    */   
        *err = OS_ERR_EVENT_TYPE;   
        return (0);   
    }   
    if (OSIntNesting > 0) {                            /* Make sure it's not called from an ISR        */   
        *err = OS_ERR_PEND_ISR;   
        return (0);   
    }   
    OS_ENTER_CRITICAL();                               /* Get value (0 or 1) of Mutex                  */   
    if ((pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8) == OS_MUTEX_AVAILABLE) {   
        pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8;   /*      Mask off LSByte (Acquire Mutex)         */   
        pevent->OSEventCnt |= OSTCBCur->OSTCBPrio;     /*      Save current task priority in LSByte    */   
        pevent->OSEventPtr  = (void *)OSTCBCur;        /*      Link TCB of task owning Mutex           */   
        OS_EXIT_CRITICAL();   
        *err = OS_NO_ERR;   
        return (1);   
    }   
    OS_EXIT_CRITICAL();   
    *err = OS_NO_ERR;   
    return (0);   
}   
#endif   
   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                  CREATE A MUTUAL EXCLUSION SEMAPHORE  
*  
* Description: This function creates a mutual exclusion semaphore.  
*  
* Arguments  : prio          is the priority to use when accessing the mutual exclusion semaphore.  In  
*                            other words, when the semaphore is acquired and a higher priority task  
*                            attempts to obtain the semaphore then the priority of the task owning the  
*                            semaphore is raised to this priority.  It is assumed that you will specify  
*                            a priority that is LOWER in value than ANY of the tasks competing for the  
*                            mutex.  
*  
*              err           is a pointer to an error code which will be returned to your application:  
*                               OS_NO_ERR           if the call was successful.  
*                               OS_ERR_CREATE_ISR   if you attempted to create a MUTEX from an ISR  
*                               OS_PRIO_EXIST       if a task at the priority inheritance priority  
*                                                   already exist.  
*                               OS_ERR_PEVENT_NULL  No more event control blocks available.  
*                               OS_PRIO_INVALID     if the priority you specify is higher that the  
*                                                   maximum allowed (i.e. > OS_LOWEST_PRIO)  
*  
* Returns    : != (void *)0  is a pointer to the event control clock (OS_EVENT) associated with the  
*                            created mutex.  
*              == (void *)0  if an error is detected.  
*  
* Note(s)    : 1) The LEAST significant 8 bits of '.OSEventCnt' are used to hold the priority number  
*                 of the task owning the mutex or 0xFF if no task owns the mutex.  
*              2) The MOST  significant 8 bits of '.OSEventCnt' are used to hold the priority number  
*                 to use to reduce priority inversion.  
*********************************************************************************************************  
*/   
   
OS_EVENT  *OSMutexCreate (INT8U prio, INT8U *err)   
{   
    OS_EVENT  *pevent;   
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
#if OS_ARG_CHK_EN > 0   
    if (err == (INT8U *)0) {                               /* Validate 'err'                           */   
        return ((OS_EVENT *)0);   
    }   
    if (prio >= OS_LOWEST_PRIO) {                          /* Validate PIP                             */   
        *err = OS_PRIO_INVALID;   
        return ((OS_EVENT *)0);   
    }   
#endif   
    if (OSIntNesting > 0) {                                /* See if called from ISR ...               */   
        *err = OS_ERR_CREATE_ISR;                          /* ... can't CREATE mutex from an ISR       */   
        return ((OS_EVENT *)0);   
    }   
    OS_ENTER_CRITICAL();   
    if (OSTCBPrioTbl[prio] != (OS_TCB *)0) {               /* Mutex priority must not already exist    */   
        OS_EXIT_CRITICAL();                                /* Task already exist at priority ...       */   
        *err = OS_PRIO_EXIST;                              /* ... inheritance priority                 */   
        return ((OS_EVENT *)0);   
    }   
    OSTCBPrioTbl[prio] = (OS_TCB *)1;                      /* Reserve the table entry                  */   
    pevent             = OSEventFreeList;                  /* Get next free event control block        */   
    if (pevent == (OS_EVENT *)0) {                         /* See if an ECB was available              */   
        OSTCBPrioTbl[prio] = (OS_TCB *)0;                  /* No, Release the table entry              */   
        OS_EXIT_CRITICAL();   
        *err               = OS_ERR_PEVENT_NULL;           /* No more event control blocks             */   
        return (pevent);   
    }   
    OSEventFreeList        = (OS_EVENT *)OSEventFreeList->OSEventPtr;   /* Adjust the free list        */   
    OS_EXIT_CRITICAL();   
    pevent->OSEventType    = OS_EVENT_TYPE_MUTEX;   
    pevent->OSEventCnt     = (INT16U)((INT16U)prio << 8) | OS_MUTEX_AVAILABLE; /* Resource is avail.   */   
    pevent->OSEventPtr     = (void *)0;                                 /* No task owning the mutex    */   
#if OS_EVENT_NAME_SIZE > 1   
    pevent->OSEventName[0] = '?';   
    pevent->OSEventName[1] = OS_ASCII_NUL;   
#endif   
    OS_EventWaitListInit(pevent);   
    *err                   = OS_NO_ERR;   
    return (pevent);   
}   
   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                          DELETE A MUTEX  
*  
* Description: This function deletes a mutual exclusion semaphore and readies all tasks pending on the it.  
*  
* Arguments  : pevent        is a pointer to the event control block associated with the desired mutex.  
*  
*              opt           determines delete options as follows:  
*                            opt == OS_DEL_NO_PEND   Delete mutex ONLY if no task pending  
*                            opt == OS_DEL_ALWAYS    Deletes the mutex even if tasks are waiting.  
*                                                    In this case, all the tasks pending will be readied.  
*  
*              err           is a pointer to an error code that can contain one of the following values:  
*                            OS_NO_ERR               The call was successful and the mutex was deleted  
*                            OS_ERR_DEL_ISR          If you attempted to delete the MUTEX from an ISR  
*                            OS_ERR_INVALID_OPT      An invalid option was specified  
*                            OS_ERR_TASK_WAITING     One or more tasks were waiting on the mutex  
*                            OS_ERR_EVENT_TYPE       If you didn't pass a pointer to a mutex  
*                            OS_ERR_PEVENT_NULL      If 'pevent' is a NULL pointer.  
*  
* Returns    : pevent        upon error  
*              (OS_EVENT *)0 if the mutex was successfully deleted.  
*  
* Note(s)    : 1) This function must be used with care.  Tasks that would normally expect the presence of  
*                 the mutex MUST check the return code of OSMutexPend().  
*              2) This call can potentially disable interrupts for a long time.  The interrupt disable  
*                 time is directly proportional to the number of tasks waiting on the mutex.  
*              3) Because ALL tasks pending on the mutex will be readied, you MUST be careful because the  
*                 resource(s) will no longer be guarded by the mutex.  
*********************************************************************************************************  
*/   
   
#if OS_MUTEX_DEL_EN   
OS_EVENT  *OSMutexDel (OS_EVENT *pevent, INT8U opt, INT8U *err)   
{   
    BOOLEAN    tasks_waiting;   
    OS_EVENT  *pevent_return;   
    INT8U      pip;   
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
#if OS_ARG_CHK_EN > 0   
    if (err == (INT8U *)0) {                               /* Validate 'err'                           */   
        return ((OS_EVENT *)0);   
    }   
    if (pevent == (OS_EVENT *)0) {                         /* Validate 'pevent'                        */   
        *err = OS_ERR_PEVENT_NULL;   
        return ((OS_EVENT *)0);   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) {      /* Validate event block type                */   
        *err = OS_ERR_EVENT_TYPE;   
        return (pevent);   
    }   
    if (OSIntNesting > 0) {                                /* See if called from ISR ...               */   
        *err = OS_ERR_DEL_ISR;                             /* ... can't DELETE from an ISR             */   
        return (pevent);   
    }   
    OS_ENTER_CRITICAL();   
    if (pevent->OSEventGrp != 0) {                         /* See if any tasks waiting on mutex        */   
        tasks_waiting = TRUE;                              /* Yes                                      */   
    } else {   
        tasks_waiting = FALSE;                             /* No                                       */   
    }   
    switch (opt) {   
        case OS_DEL_NO_PEND:                               /* Delete mutex only if no task waiting     */   
             if (tasks_waiting == FALSE) {   
#if OS_EVENT_NAME_SIZE > 1   
                 pevent->OSEventName[0] = '?';             /* Unknown name                             */   
                 pevent->OSEventName[1] = OS_ASCII_NUL;   
#endif   
                 pip                 = (INT8U)(pevent->OSEventCnt >> 8);   
                 OSTCBPrioTbl[pip]   = (OS_TCB *)0;        /* Free up the PIP                          */   
                 pevent->OSEventType = OS_EVENT_TYPE_UNUSED;   
                 pevent->OSEventPtr  = OSEventFreeList;    /* Return Event Control Block to free list  */   
                 pevent->OSEventCnt  = 0;   
                 OSEventFreeList     = pevent;   
                 OS_EXIT_CRITICAL();   
                 *err                = OS_NO_ERR;   
                 pevent_return       = (OS_EVENT *)0;      /* Mutex has been deleted                   */   
             } else {   
                 OS_EXIT_CRITICAL();   
                 *err                = OS_ERR_TASK_WAITING;   
                 pevent_return       = pevent;   
             }   
             break;   
   
        case OS_DEL_ALWAYS:                                /* Always delete the mutex                  */   
             while (pevent->OSEventGrp != 0) {             /* Ready ALL tasks waiting for mutex        */   
                 (void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MUTEX);   
             }   
#if OS_EVENT_NAME_SIZE > 1   
             pevent->OSEventName[0] = '?';                 /* Unknown name                             */   
             pevent->OSEventName[1] = OS_ASCII_NUL;   
#endif   
             pip                 = (INT8U)(pevent->OSEventCnt >> 8);   
             OSTCBPrioTbl[pip]   = (OS_TCB *)0;            /* Free up the PIP                          */   
             pevent->OSEventType = OS_EVENT_TYPE_UNUSED;   
             pevent->OSEventPtr  = OSEventFreeList;        /* Return Event Control Block to free list  */   
             pevent->OSEventCnt  = 0;   
             OSEventFreeList     = pevent;                 /* Get next free event control block        */   
             OS_EXIT_CRITICAL();   
             if (tasks_waiting == TRUE) {                  /* Reschedule only if task(s) were waiting  */   
                 OS_Sched();                               /* Find highest priority task ready to run  */   
             }   
             *err          = OS_NO_ERR;   
             pevent_return = (OS_EVENT *)0;                /* Mutex has been deleted                   */   
             break;   
   
        default:   
             OS_EXIT_CRITICAL();   
             *err          = OS_ERR_INVALID_OPT;   
             pevent_return = pevent;   
             break;   
    }   
    return (pevent_return);   
}   
#endif   
   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                  PEND ON MUTUAL EXCLUSION SEMAPHORE  
*  
* Description: This function waits for a mutual exclusion semaphore.  
*  
* Arguments  : pevent        is a pointer to the event control block associated with the desired  
*                            mutex.  
*  
*              timeout       is an optional timeout period (in clock ticks).  If non-zero, your task will  
*                            wait for the resource up to the amount of time specified by this argument.  
*                            If you specify 0, however, your task will wait forever at the specified  
*                            mutex or, until the resource becomes available.  
*  
*              err           is a pointer to where an error message will be deposited.  Possible error  
*                            messages are:  
*                               OS_NO_ERR          The call was successful and your task owns the mutex  
*                               OS_TIMEOUT         The mutex was not available within the specified time.  
*                               OS_ERR_EVENT_TYPE  If you didn't pass a pointer to a mutex  
*                               OS_ERR_PEVENT_NULL 'pevent' is a NULL pointer  
*                               OS_ERR_PEND_ISR    If you called this function from an ISR and the result  
*                                                  would lead to a suspension.  
*                               OS_ERR_PIP_LOWER   If the priority of the task that owns the Mutex is  
*                                                  HIGHER (i.e. a lower number) than the PIP.  This error  
*                                                  indicates that you did not set the PIP higher (lower  
*                                                  number) than ALL the tasks that compete for the Mutex.  
*                                                  Unfortunately, this is something that could not be  
*                                                  detected when the Mutex is created because we don't know  
*                                                  what tasks will be using the Mutex.  
*  
* Returns    : none  
*  
* Note(s)    : 1) The task that owns the Mutex MUST NOT pend on any other event while it owns the mutex.  
*              2) You MUST NOT change the priority of the task that owns the mutex  
*********************************************************************************************************  
*/   
void  OSMutexPend (OS_EVENT *pevent, INT16U timeout, INT8U *err)   
{   
    INT8U      pip;                                        /* Priority Inheritance Priority (PIP)      */   
    INT8U      mprio;                                      /* Mutex owner priority                     */   
    BOOLEAN    rdy;                                        /* Flag indicating task was ready           */   
    OS_TCB    *ptcb;   
    OS_EVENT  *pevent2;   
    INT8U      y;   
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
#if OS_ARG_CHK_EN > 0   
    if (err == (INT8U *)0) {                               /* Validate 'err'                           */   
        return;   
    }   
    if (pevent == (OS_EVENT *)0) {                         /* Validate 'pevent'                        */   
        *err = OS_ERR_PEVENT_NULL;   
        return;   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) {      /* Validate event block type                */   
        *err = OS_ERR_EVENT_TYPE;   
        return;   
    }   
    if (OSIntNesting > 0) {                                /* See if called from ISR ...               */   
        *err = OS_ERR_PEND_ISR;                            /* ... can't PEND from an ISR               */   
        return;   
    }   
    OS_ENTER_CRITICAL();                                   
    pip = (INT8U)(pevent->OSEventCnt >> 8);                /* Get PIP from mutex                       */   
                                                           /* Is Mutex available?                      */   
    if ((INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8) == OS_MUTEX_AVAILABLE) {   
        pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8;       /* Yes, Acquire the resource                */   
        pevent->OSEventCnt |= OSTCBCur->OSTCBPrio;         /*      Save priority of owning task        */   
        pevent->OSEventPtr  = (void *)OSTCBCur;            /*      Point to owning task's OS_TCB       */   
        if (OSTCBCur->OSTCBPrio <= pip) {                  /*      PIP 'must' have a SMALLER prio ...  */   
            OS_EXIT_CRITICAL();                            /*      ... than current task!              */   
            *err  = OS_ERR_PIP_LOWER;   
        } else {   
            OS_EXIT_CRITICAL();   
            *err  = OS_NO_ERR;   
        }   
        return;   
    }   
    mprio = (INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8);  /* No, Get priority of mutex owner   */   
    ptcb  = (OS_TCB *)(pevent->OSEventPtr);                       /*     Point to TCB of mutex owner   */   
    if (ptcb->OSTCBPrio > pip) {                                  /*     Need to promote prio of owner?*/   
        if (mprio > OSTCBCur->OSTCBPrio) {   
            y = ptcb->OSTCBY;   
            if ((OSRdyTbl[y] & ptcb->OSTCBBitX) != 0) {           /*     See if mutex owner is ready   */   
                OSRdyTbl[y] &= ~ptcb->OSTCBBitX;                  /*     Yes, Remove owner from Rdy ...*/   
                if (OSRdyTbl[y] == 0) {                           /*          ... list at current prio */   
                    OSRdyGrp &= ~ptcb->OSTCBBitY;   
                }   
                rdy = TRUE;   
            } else {   
                pevent2 = ptcb->OSTCBEventPtr;   
                if (pevent2 != (OS_EVENT *)0) {                   /* Remove from event wait list       */   
                    if ((pevent2->OSEventTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) {   
                        pevent2->OSEventGrp &= ~ptcb->OSTCBBitY;   
                    }   
                }   
                rdy = FALSE;                               /* No                                       */   
            }   
            ptcb->OSTCBPrio = pip;                         /* Change owner task prio to PIP            */   
#if OS_LOWEST_PRIO <= 63   
            ptcb->OSTCBY    =  ptcb->OSTCBPrio >> 3;   
            ptcb->OSTCBX    =  ptcb->OSTCBPrio & 0x07;   
#else   
            ptcb->OSTCBY    = (ptcb->OSTCBPrio >> 4) & 0xFF;   
            ptcb->OSTCBX    =  ptcb->OSTCBPrio & 0x0F;   
#endif   
            ptcb->OSTCBBitY = 1 << ptcb->OSTCBY;   
            ptcb->OSTCBBitX = 1 << ptcb->OSTCBX;   
            if (rdy == TRUE) {                             /* If task was ready at owner's priority ...*/   
                OSRdyGrp               |= ptcb->OSTCBBitY; /* ... make it ready at new priority.       */   
                OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;   
            } else {   
                pevent2 = ptcb->OSTCBEventPtr;   
                if (pevent2 != (OS_EVENT *)0) {            /* Remove from event wait list              */   
                    pevent2->OSEventGrp               |= ptcb->OSTCBBitY;   
                    pevent2->OSEventTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;   
                }   
            }   
            OSTCBPrioTbl[pip] = ptcb;   
        }   
    }   
    OSTCBCur->OSTCBStat   |= OS_STAT_MUTEX;           /* Mutex not available, pend current task        */   
    OSTCBCur->OSTCBPendTO  = FALSE;   
    OSTCBCur->OSTCBDly     = timeout;                 /* Store timeout in current task's TCB           */   
    OS_EventTaskWait(pevent);                         /* Suspend task until event or timeout occurs    */   
    OS_EXIT_CRITICAL();   
    OS_Sched();                                       /* Find next highest priority task ready         */   
    OS_ENTER_CRITICAL();   
    if (OSTCBCur->OSTCBPendTO == TRUE) {              /* See if we timed out during the pend           */   
        OS_EventTO(pevent);   
        OS_EXIT_CRITICAL();   
        *err = OS_TIMEOUT;                            /* Indicate that we didn't get mutex within TO   */   
        return;   
    }   
    OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;   
    OS_EXIT_CRITICAL();   
    *err = OS_NO_ERR;   
}   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                  POST TO A MUTUAL EXCLUSION SEMAPHORE  
*  
* Description: This function signals a mutual exclusion semaphore  
*  
* Arguments  : pevent              is a pointer to the event control block associated with the desired  
*                                  mutex.  
*  
* Returns    : OS_NO_ERR               The call was successful and the mutex was signaled.  
*              OS_ERR_EVENT_TYPE       If you didn't pass a pointer to a mutex  
*              OS_ERR_PEVENT_NULL      'pevent' is a NULL pointer  
*              OS_ERR_POST_ISR         Attempted to post from an ISR (not valid for MUTEXes)  
*              OS_ERR_NOT_MUTEX_OWNER  The task that did the post is NOT the owner of the MUTEX.  
*********************************************************************************************************  
*/   
   
INT8U  OSMutexPost (OS_EVENT *pevent)   
{   
    INT8U      pip;                                   /* Priority inheritance priority                 */   
    INT8U      prio;   
    INT8U      y;   
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
    if (OSIntNesting > 0) {                           /* See if called from ISR ...                    */   
        return (OS_ERR_POST_ISR);                     /* ... can't POST mutex from an ISR              */   
    }   
#if OS_ARG_CHK_EN > 0   
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */   
        return (OS_ERR_PEVENT_NULL);   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type                     */   
        return (OS_ERR_EVENT_TYPE);   
    }   
    OS_ENTER_CRITICAL();   
    pip  = (INT8U)(pevent->OSEventCnt >> 8);          /* Get priority inheritance priority of mutex    */   
    prio = (INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8);  /* Get owner's original priority      */   
    if (OSTCBCur != (OS_TCB *)pevent->OSEventPtr) {   /* See if posting task owns the MUTEX            */   
        OS_EXIT_CRITICAL();   
        return (OS_ERR_NOT_MUTEX_OWNER);   
    }   
    if (OSTCBCur->OSTCBPrio == pip) {                 /* Did we have to raise current task's priority? */   
        y            = OSTCBCur->OSTCBY;              /* Yes, Return to original priority              */   
        OSRdyTbl[y] &= ~OSTCBCur->OSTCBBitX;          /*      Remove owner from ready list at 'pip'    */   
        if (OSRdyTbl[y] == 0) {   
            OSRdyGrp &= ~OSTCBCur->OSTCBBitY;   
        }   
        OSTCBCur->OSTCBPrio         = prio;   
#if OS_LOWEST_PRIO <= 63   
        OSTCBCur->OSTCBY            = prio >> 3;   
        OSTCBCur->OSTCBX            = prio & 0x07;   
#else   
        OSTCBCur->OSTCBY            = (prio >> 4) & 0xFF;   
        OSTCBCur->OSTCBX            = prio & 0x0F;   
#endif   
        OSTCBCur->OSTCBBitY         = 1 << OSTCBCur->OSTCBY;   
        OSTCBCur->OSTCBBitX         = 1 << OSTCBCur->OSTCBX;   
        OSRdyGrp                   |= OSTCBCur->OSTCBBitY;   
        OSRdyTbl[OSTCBCur->OSTCBY] |= OSTCBCur->OSTCBBitX;   
        OSTCBPrioTbl[prio]          = OSTCBCur;   
    }   
    OSTCBPrioTbl[pip] = (OS_TCB *)1;                  /* Reserve table entry                           */   
    if (pevent->OSEventGrp != 0) {                    /* Any task waiting for the mutex?               */   
                                                      /* Yes, Make HPT waiting for mutex ready         */   
        prio                = OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MUTEX);   
        pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8;  /*      Save priority of mutex's new owner       */   
        pevent->OSEventCnt |= prio;   
        pevent->OSEventPtr  = OSTCBPrioTbl[prio];     /*      Link to mutex owner's OS_TCB             */   
        OS_EXIT_CRITICAL();   
        OS_Sched();                                   /*      Find highest priority task ready to run  */   
        return (OS_NO_ERR);   
    }   
    pevent->OSEventCnt |= OS_MUTEX_AVAILABLE;         /* No,  Mutex is now available                   */   
    pevent->OSEventPtr  = (void *)0;   
    OS_EXIT_CRITICAL();   
    return (OS_NO_ERR);   
}   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                     QUERY A MUTUAL EXCLUSION SEMAPHORE  
*  
* Description: This function obtains information about a mutex  
*  
* Arguments  : pevent          is a pointer to the event control block associated with the desired mutex  
*  
*              p_mutex_data    is a pointer to a structure that will contain information about the mutex  
*  
* Returns    : OS_NO_ERR            The call was successful and the message was sent  
*              OS_ERR_QUERY_ISR     If you called this function from an ISR  
*              OS_ERR_PEVENT_NULL   If 'pevent'       is a NULL pointer  
*              OS_ERR_PDATA_NULL    If 'p_mutex_data' is a NULL pointer  
*              OS_ERR_EVENT_TYPE    If you are attempting to obtain data from a non mutex.  
*********************************************************************************************************  
*/   
   
#if OS_MUTEX_QUERY_EN > 0   
INT8U  OSMutexQuery (OS_EVENT *pevent, OS_MUTEX_DATA *p_mutex_data)   
{   
    INT8U      i;   
#if OS_LOWEST_PRIO <= 63   
    INT8U     *psrc;   
    INT8U     *pdest;   
#else   
    INT16U    *psrc;   
    INT16U    *pdest;   
#endif   
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
    if (OSIntNesting > 0) {                                /* See if called from ISR ...               */   
        return (OS_ERR_QUERY_ISR);                         /* ... can't QUERY mutex from an ISR        */   
    }   
#if OS_ARG_CHK_EN > 0   
    if (pevent == (OS_EVENT *)0) {                         /* Validate 'pevent'                        */   
        return (OS_ERR_PEVENT_NULL);   
    }   
    if (p_mutex_data == (OS_MUTEX_DATA *)0) {              /* Validate 'p_mutex_data'                  */   
        return (OS_ERR_PDATA_NULL);   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) {      /* Validate event block type                */   
        return (OS_ERR_EVENT_TYPE);   
    }   
    OS_ENTER_CRITICAL();   
    p_mutex_data->OSMutexPIP  = (INT8U)(pevent->OSEventCnt >> 8);   
    p_mutex_data->OSOwnerPrio = (INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8);   
    if (p_mutex_data->OSOwnerPrio == 0xFF) {   
        p_mutex_data->OSValue = 1;   
    } else {   
        p_mutex_data->OSValue = 0;   
    }   
    p_mutex_data->OSEventGrp  = pevent->OSEventGrp;        /* Copy wait list                           */   
    psrc                      = &pevent->OSEventTbl[0];   
    pdest                     = &p_mutex_data->OSEventTbl[0];   
    for (i = 0; i < OS_EVENT_TBL_SIZE; i++) {   
        *pdest++ = *psrc++;   
    }   
    OS_EXIT_CRITICAL();   
    return (OS_NO_ERR);   
}   
#endif                                                     /* OS_MUTEX_QUERY_EN                        */   
#endif                                                     /* OS_MUTEX_EN                              */   

